Tobacco Budworm Resistance: Commercial Cultivars and Advanced Breeding Likes

Jack C. McCarty, Jr.


 
ABSTRACT

Research has been underway for a number of years to develop effective plant resistance to the tobacco budworm, Heliothis virescens (F.). As a result plant breeders have developed strains of cotton, Gossypium hirsutum L., which carry resistance to this economic pest. During 1988 and 1989, 22 and 15 advanced breeding lines respectively, were evaluated for resistance to the tobacco budworm. These breed lines were from 9 public or private cotton research programs. During this same time period 24 commercial 11 cultivars were evaluated for resistance in adjacent tests.

To evaluate resistance the various cottons were grown with insecticide protection and under artificial ratio inoculations with tobacco budworm larvae. The ratio of a cotton's yield when infested to its yield insecticide protection was used as a measure of resistance

The mean yield of the advanced breeding lines in 1988 was 1115 and 1291 lbs of lint/acre, respectively when grown with and without tobacco budworms or produced 86% of their yield when protected from tobacco budworms. Under the same conditions the heck a cultivar 'DES 119' yielded 1340 and 1648 lb/a or 81% of its protected yield. The mean of the top 2 advanced breeding lines yielded 1521 when infested and 1716 lbs/acre when protected or 89% ox their protected yield.

In 1989 under severe tobacco budworm pressure the mean yield (lbs of lint/acre) was 420 infested and 957 protected or 45% of protected yield. The mean of the check cultivars, 'DES 119 and Deltapine 50' was 400 and 1123 or 36% of their protected yield. The mean of the top 2 entries yielded 655 infested and 1197 protected or 55% of protected yield. During both years the advanced breeding lines produced about 10% more of their protected yield than the commercial checks. The top entries in these tests produced higher yields under infestation and the equivalent yield when protected as compared with the commercial check. The mean yield of the commercial cultivars evaluated in 1988 was 1122 and 1523 lbs of lint/acre when grown with and without tobacco budworms, or they yielded 74% of their protected yield. The mean of the top 2 cultivars yielded 1283 and 1651 lbs of lint/acre when infested and protected or 78% of protected yield. Under the severe pressure of 1989 the mean yield was 456 and 1333 lbs of lint/acre when infested and protected or 36% of protected yield. The top 2 cultivate yielded 610 and 1499 or 41% of protected yield.

During two years of testing the advanced breeding lines on the average yielded approximately 10% more of their protected yield as compared with the commercial cultivars. The best advanced breeding lines yielded more under infestation and less under protection when compared to the leading commercial cultivars. These test show that cotton breeders have been able to a combine tobacco budworm resistance with good yield ability.



Reprinted from 1990 Proceedings: Beltwide Cotton Production Research Conferences pg. 84
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998